Check a billIs My Energy Direct Debit Correct? UK Calculator
Use this calculator before accepting a direct debit increase or asking for a reduction. It turns the supplier’s forecast, balance and buffer logic into a number you can challenge in writing.
The short answer
A fair direct debit is not just annual cost divided by 12. It should also reflect current credit, account debt, recovery period, seasonal buffer and the supplier’s latest forecast. Use this calculator to see whether the proposed amount is broadly plausible or needs a written challenge.
Energy direct debit calculator
Enter your numbers to compare.
This is a sense-check. It does not reproduce any supplier’s internal forecast model and is not financial or legal advice.
What number should I enter?
| Input | Use this | Avoid this mistake |
|---|---|---|
| Annual forecast | Use a recent annual estimate or actual annual cost if reliable. | Do not use one abnormal winter bill as a full-year forecast. |
| Credit | Use credit that still exists after the latest bill. | Do not count credit that has already been spent by new charges. |
| Debt | Use account debt the supplier is trying to recover. | Do not mix genuine debt with a disputed old balance without checking it. |
| Buffer | Use a modest end-of-year buffer. | Do not accept a large unexplained buffer without asking why. |
| Months | Use the period the supplier says it is smoothing over. | Do not assume it is always 12 months. |
When the payment looks too high
- Ask for the annual usage forecast.
- Ask how current credit or debt was used.
- Ask what buffer they are holding and why.
- Ask for the next review date.
When the bill may be the real issue
- Wrong or estimated reading.
- Back billing or old charges.
- Smart meter stopped sending readings.
- Tariff or standing charge changed.
Direct debit challenge wording
Please explain how my proposed direct debit of £[amount] was calculated.
In particular, please confirm the annual usage forecast, current account balance, any debt recovery amount, the buffer being held and the review period used.
Based on my calculation, a reasonable monthly amount appears closer to £[your figure].
If you disagree, please provide a written breakdown showing why the higher amount is necessary.
Frequently asked questions
Can this calculator prove my supplier is wrong?
No. It is a sense-check. It helps you ask better questions about forecast, credit, debt, buffer and review period.
Why did my supplier increase my direct debit if I am in credit?
They may be forecasting higher future use or trying to hold a buffer. Ask for the calculation and current balance treatment in writing.
Should I cancel the direct debit?
Do not cancel without understanding consequences. First ask the supplier to explain and review the amount in writing.
Official sources used for this page
BillDecoded translates official process and billing information into practical checks. It is not affiliated with the Ombudsman, Ofgem, Citizens Advice, Which? or any supplier.